1. Technical Field
The present invention relates to a bush component force detection device that detects a component force acting on a bush which is provided in a connecting portion of a structural member of a vehicle.
2. Related Art
The suspension of a vehicle has an effect on riding comfort and driving stability of the vehicle, and so component forces of the suspension are measured to evaluate the riding comfort and driving stability of the vehicle. A vehicle is designed based on the evaluation of the riding comfort and driving stability of the vehicle. Therefore, the riding comfort and driving stability of a vehicle can be improved by accurately measuring dynamic change in each component force in portions of the suspension.
Various methods have been proposed to detect changes in component forces such as yaw, pitch, and roll which act on the portions of the suspension mechanism. For example, Japanese Unexamined Patent Application Publication No. 2011-85514 discloses a load measurement sensor which includes a plurality of strain gauges and is tightly fixed to a rod-like body such as a damper in the suspension mechanism of a vehicle.
Here, shafts, which serve as connecting portions between the frame of the vehicle and an arm member, are base points for allowing the arm member to be moved, and thus for the design and adjustment of the suspension mechanism, it is necessary to detect component forces in the connecting portions between the frame and the arm member with high accuracy.
However, even if a sensor is mounted on a damper, an arm member or the like as described above for measuring the behavior of each of the portions of the suspension, the behavior of each shaft (movable connecting portion of each member) may not be measured accurately. That is, in order to measure the behavior of each shaft of the suspension, calculation is performed based on a result of measurement made by a sensor which is mounted on an arm or a damper connected to the shaft to be measured, and thus the calculation gives only a predicted value. Particularly, when an elastic body is used such as a rubber bush which serves as a bearing of the suspension, it is necessary to take spring characteristics and holes into consideration, and thus such a predicted value may be much different from an actual component force. Though it is possible to mount a sensor on the bearing itself, the mounting space for the sensor needs to be ensured in this case by reducing the bearing in size, then not only the production cost will increase but also the spring characteristics of the bearing will change, and thus an adverse effect on the design may be caused.